There are many arrangements wherein conveyors buffer flow of articles through a system. One common use is in systems for filling liquid containers such as bottles, cans or boxes. In such systems, to achieve first-in/first-out flow, an accumulator with oppositely-running conveyors can be located between an upstream station (e.g., a filler) and a downstream station (e.g. a capper). The conveyors may be straight and horizontal, and may be in the form of “mass-flow, linear” conveyors. Alternatively, the conveyors may be curved and non-horizontal, and may be in the form of “single-file, helical” conveyors. One of the conveyors (e.g., an infeed conveyor) receives articles from the system and the other conveyor (e.g., an outfeed conveyor) returns articles to the system. A transfer device moves articles from the infeed conveyor to the outfeed conveyor. Articles thus flow from the system, through the infeed conveyor, transfer device, and outfeed conveyor, and then back to the system.
When the upstream and downstream stations run at the same speed (in terms of articles per minute, for example), the accumulator generally operates in a steady state. When the infeed and outfeed conveyors are moved at the same speed the transfer device is stationary. If the downstream station slows or stops, the device leaves steady state. The outfeed conveyor slows or stops accordingly, while the infeed conveyor continues and the transfer device moves so that more articles enter the accumulator. As long as the downstream station returns to service before the accumulator is filled, then the overall system need not be stopped or slowed. Similarly, if the upstream device slows or stops, the infeed conveyor slows or stops accordingly, and the outfeed conveyor continues at full speed as long as a supply of articles is available in the accumulator. As long as the upstream device returns to service before the accumulator is emptied, then the overall system need not be stopped or slowed.
Many of such accumulator devices have been successfully deployed. In particular, Applicant has commercially introduced, and is owner of U.S. patents on, various types of mass-flow and single file accumulators under the DYNAC® name. For example, U.S. Pat. Nos. 6,382,398 and 6,497,321 disclose respectively horizontal, mass-flow and helical, single-file accumulators. These patents are incorporated by reference herein.
The devices and systems introduced by Applicant and disclosed in the above patents provide exemplary operation in their intended systems. Further, available floorspace, customer preference and/or the particular type (or types) of articles to be handled by a given system may dictate which of the above types of accumulators might be employed. However, no available system provides the high capacity/easy reach benefits of a horizontal, mass-flow system and the secure handling/reduced floorspace of helical, single-file systems.
Therefore, further improvement in accumulator devices and systems would be welcome, in particular in providing one or more of designs for first-in/first-out accumulators, having high capacity, a single file output, and/or an efficient floorspace arrangement, as well as other advantages.